smbw.c

samba-3.0.22.tar.gz 编译smb服务器的源码

/* 
   Unix SMB/Netbios implementation.
   Version 2.0
   SMB wrapper functions
   Copyright (C) Andrew Tridgell 1998
   Copyright (C) Derrell Lipman 2003-2005
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdarg.h>
#include <assert.h>
#include "smbw.h"
#include "bsd-strlfunc.h"

typedef enum StartupType
{
        StartupType_Fake,
        StartupType_Real
} StartupType;

int smbw_fd_map[__FD_SETSIZE];
int smbw_ref_count[__FD_SETSIZE];
char smbw_cwd[PATH_MAX];
char smbw_prefix[] = SMBW_PREFIX;

/* needs to be here because of dumb include files on some systems */
int creat_bits = O_WRONLY|O_CREAT|O_TRUNC;

int smbw_initialized = 0;

static int debug_level = 0;

static SMBCCTX *smbw_ctx;

extern int smbw_debug;


/*****************************************************
smbw_ref -- manipulate reference counts
******************************************************/
int smbw_ref(int client_fd, Ref_Count_Type type, ...)
{
        va_list ap;

        /* client id values begin at SMBC_BASE_FC. */
        client_fd -= SMBC_BASE_FD;

        va_start(ap, type);
        switch(type)
        {
        case SMBW_RCT_Increment:
                return ++smbw_ref_count[client_fd];

        case SMBW_RCT_Decrement:
                return --smbw_ref_count[client_fd];

        case SMBW_RCT_Get:
                return smbw_ref_count[client_fd];

        case SMBW_RCT_Set:
                return (smbw_ref_count[client_fd] = va_arg(ap, int));
        }
        va_end(ap);

        /* never gets here */
        return -1;
}


/*
 * Return a username and password given a server and share name
 *
 * Returns 0 upon success;
 * non-zero otherwise, and errno is set to indicate the error.
 */
static void get_envvar_auth_data(const char *srv, 
                                 const char *shr,
                                 char *wg, int wglen, 
                                 char *un, int unlen,
                                 char *pw, int pwlen)
{
        char *u;
        char *p;
        char *w;

	/* Fall back to environment variables */

	w = getenv("WORKGROUP");
	if (w == NULL) w = "";

	u = getenv("USER");
	if (u == NULL) u = "";

	p = getenv("PASSWORD");
	if (p == NULL) p = "";

        smbw_strlcpy(wg, w, wglen);
        smbw_strlcpy(un, u, unlen);
        smbw_strlcpy(pw, p, pwlen);
}

static smbc_get_auth_data_fn get_auth_data_fn = get_envvar_auth_data;

/*****************************************************
set the get auth data function
******************************************************/
void smbw_set_auth_data_fn(smbc_get_auth_data_fn fn)
{
	get_auth_data_fn = fn;
}


/*****************************************************
ensure that all connections are terminated upon exit
******************************************************/
static void do_shutdown(void)
{
        if (smbw_ctx != NULL) {
                smbc_free_context(smbw_ctx, 1);
        }
}


/***************************************************** 
initialise structures
*******************************************************/
static void do_init(StartupType startupType)
{
        int i;
        char *p;

	smbw_initialized = 1;   /* this must be first to avoid recursion! */

        smbw_ctx = NULL;        /* don't free context until it's established */

        /* initially, no file descriptors are mapped */
        for (i = 0; i < __FD_SETSIZE; i++) {
                smbw_fd_map[i] = -1;
                smbw_ref_count[i] = 0;
        }

        /* See if we've been told to start in a particular directory */
        if ((p=getenv("SMBW_DIR")) != NULL) {
                smbw_strlcpy(smbw_cwd, p, PATH_MAX);

                /* we don't want the old directory to be busy */
                (* smbw_libc.chdir)("/");
                
        } else {
                *smbw_cwd = '\0';
        }

	if ((p=getenv("DEBUG"))) {
		debug_level = atoi(p);
	}

        if ((smbw_ctx = smbc_new_context()) == NULL) {
                fprintf(stderr, "Could not create a context.\n");
                exit(1);
        }
        
        smbw_ctx->debug = debug_level;
        smbw_ctx->callbacks.auth_fn = get_auth_data_fn;
        smbw_ctx->options.browse_max_lmb_count = 0;
        smbw_ctx->options.urlencode_readdir_entries = 1;
        smbw_ctx->options.one_share_per_server = 1;
        
        if (smbc_init_context(smbw_ctx) == NULL) {
                fprintf(stderr, "Could not initialize context.\n");
                exit(1);
        }
                
        smbc_set_context(smbw_ctx);

        /* if not real startup, exit handler has already been established */
        if (startupType == StartupType_Real) {
            atexit(do_shutdown);
        }
}

/***************************************************** 
initialise structures, real start up vs a fork()
*******************************************************/
void smbw_init(void)
{
    do_init(StartupType_Real);
}


/***************************************************** 
determine if a file descriptor is a smb one
*******************************************************/
int smbw_fd(int smbw_fd)
{
        SMBW_INIT();

        return (smbw_fd >= 0 &&
                smbw_fd < __FD_SETSIZE &&
                smbw_fd_map[smbw_fd] >= SMBC_BASE_FD); /* minimum smbc_ fd */
}


/***************************************************** 
determine if a path is a smb one
*******************************************************/
int smbw_path(const char *name)
{
        int len;
        int ret;
        int saved_errno;

        saved_errno = errno;

        SMBW_INIT();

        len = strlen(smbw_prefix);

        ret = ((strncmp(name, smbw_prefix, len) == 0 &&
                (name[len] == '\0' || name[len] == '/')) ||
               (*name != '/' && *smbw_cwd != '\0'));

        errno = saved_errno;
        return ret;
}


/***************************************************** 
remove redundent stuff from a filename
*******************************************************/
void smbw_clean_fname(char *name)
{
	char *p, *p2;
	int l;
	int modified = 1;

	if (!name) return;

        DEBUG(10, ("Clean [%s]...\n", name));

	while (modified) {
		modified = 0;

		if ((p=strstr(name,"/./"))) {
			modified = 1;
			while (*p) {
				p[0] = p[2];
				p++;
			}
                        DEBUG(10, ("\tclean 1 (/./) produced [%s]\n", name));
		}

		if ((p=strstr(name,"//"))) {
			modified = 1;
			while (*p) {
				p[0] = p[1];
				p++;
			}
                        DEBUG(10, ("\tclean 2 (//) produced [%s]\n", name));
		}

		if (strcmp(name,"/../")==0) {
			modified = 1;
			name[1] = 0;
                        DEBUG(10,("\tclean 3 (^/../$) produced [%s]\n", name));
		}

		if ((p=strstr(name,"/../"))) {
			modified = 1;
			for (p2 = (p > name ? p-1 : p); p2 > name; p2--) {
				if (p2[0] == '/') break;
			}
                        if (p2 > name) p2++;
			while (*p2) {
				p2[0] = p[3];
				p2++;
                                p++;
			}
                        DEBUG(10, ("\tclean 4 (/../) produced [%s]\n", name));
		}

		if (strcmp(name,"/..")==0) {
			modified = 1;
			name[1] = 0;
                        DEBUG(10, ("\tclean 5 (^/..$) produced [%s]\n", name));
		}

		l = strlen(name);
		p = l>=3?(name+l-3):name;
		if (strcmp(p,"/..")==0) {
			modified = 1;
			for (p2=p-1;p2>name;p2--) {
				if (p2[0] == '/') break;
			}
			if (p2==name) {
				p[0] = '/';
				p[1] = 0;
			} else {
				p2[0] = 0;
			}
                        DEBUG(10, ("\tclean 6 (/..) produced [%s]\n", name));
		}

		l = strlen(name);
		p = l>=2?(name+l-2):name;
		if (strcmp(p,"/.")==0) {
                        modified = 1;
			if (p == name) {
				p[1] = 0;
			} else {
				p[0] = 0;
			}
                        DEBUG(10, ("\tclean 7 (/.) produced [%s]\n", name));
		}

		if (strncmp(p=name,"./",2) == 0) {      
			modified = 1;
			do {
				p[0] = p[2];
			} while (*p++);
                        DEBUG(10, ("\tclean 8 (^./) produced [%s]\n", name));
		}

		l = strlen(p=name);
		if (l > 1 && p[l-1] == '/') {
			modified = 1;
			p[l-1] = 0;
                        DEBUG(10, ("\tclean 9 (/) produced [%s]\n", name));
		}
	}
}

void smbw_fix_path(const char *src, char *dest)
{
        const char *p;
        int len = strlen(smbw_prefix);

        if (*src == '/') {
                for (p = src + len; *p == '/'; p++)
                        ;
                snprintf(dest, PATH_MAX, "smb://%s", p);
        } else {
                snprintf(dest, PATH_MAX, "%s/%s", smbw_cwd, src);
        }

        smbw_clean_fname(dest + 5);

        DEBUG(10, ("smbw_fix_path(%s) returning [%s]\n", src, dest));
}



/***************************************************** 
a wrapper for open()
*******************************************************/
int smbw_open(const char *fname, int flags, mode_t mode)
{
        int client_fd;
        int smbw_fd;
	char path[PATH_MAX];

	SMBW_INIT();

	if (!fname) {
		errno = EINVAL;
		return -1;
	}

	smbw_fd = (smbw_libc.open)(SMBW_DUMMY, O_WRONLY, 0200);
	if (smbw_fd == -1) {
		errno = EMFILE;
                return -1;
	}

        smbw_fix_path(fname, path);
        if (flags == creat_bits) {
                client_fd =  smbc_creat(path, mode);
        } else {
                client_fd = smbc_open(path, flags, mode);
        }

        if (client_fd < 0) {
                (* smbw_libc.close)(smbw_fd);
                return -1;
        }

        smbw_fd_map[smbw_fd] = client_fd;
        smbw_ref(client_fd, SMBW_RCT_Increment);
        return smbw_fd;
}


/***************************************************** 
a wrapper for pread()

there should really be an smbc_pread() to avoid the two
lseek()s required in this kludge.
*******************************************************/
ssize_t smbw_pread(int smbw_fd, void *buf, size_t count, SMBW_OFF_T ofs)
{
        int client_fd;
	ssize_t ret;
        int saved_errno;
        SMBW_OFF_T old_ofs;
        
        if (count == 0) {
                return 0;
        }

        client_fd = smbw_fd_map[smbw_fd];

        if ((old_ofs = smbc_lseek(client_fd, 0, SEEK_CUR)) < 0 ||
            smbc_lseek(client_fd, ofs, SEEK_SET) < 0) {
                return -1;
        }

        if ((ret = smbc_read(client_fd, buf, count)) < 0) {
                saved_errno = errno;
                (void) smbc_lseek(client_fd, old_ofs, SEEK_SET);
                errno = saved_errno;
                return -1;
        }

        return ret;
}

/***************************************************** 
a wrapper for read()
*******************************************************/
ssize_t smbw_read(int smbw_fd, void *buf, size_t count)
{
        int client_fd;
        
        client_fd = smbw_fd_map[smbw_fd];

        return smbc_read(client_fd, buf, count);
}

	

/***************************************************** 
a wrapper for write()
*******************************************************/
ssize_t smbw_write(int smbw_fd, void *buf, size_t count)
{
        int client_fd;

        client_fd = smbw_fd_map[smbw_fd];

        return smbc_write(client_fd, buf, count);